The present invention relates to an air-mix door control device for an automobile air-conditioning system.
In an automobile air-conditioning system, an actual opening position of an air-mix door which adjusts a mix ratio of cold air and warm air is detected by a potentiometer, for example, and based on this detection, a motor actuator which drives the air-mix door is controlled so that the air-mix door reaches a target opening position. Because of this, if the potentiometer causes trouble due to some reason, it is not possible to detect the actual opening position of the air-mix door, disabling a control to the target opening position of the air-mix door, and thus a significant hitch occurs in air-conditioning control.
From the viewpoint as described above, in a prior art, when potentiometer for detecting an actual opening position of an air-mix door causes a trouble, the air-mix door is driven forcibly to a full-hot position or a full-cool position based on whether a target opening position of the air-mix door is in a full-hot direction or a full-cool direction. That is, the air-mix door is driven forcibly to a full-hot position when the target opening position is in a full-hot side, and is driven forcibly to a full-cool position when the target opening position is in a full-cool side. By this, it is designed to secure at least cooling or heating.
However, according to a method like this, since the air-mix door is only driven forcibly to the full-hot position or the full-cool position in the case of potentiometer trouble, there is a problem that an air-conditioning feeling is noticeably compromised.